I have three Adire Audio Shiva mkIII 12"'s in a custom 3.6ft^3 box. The box is 3/4" MDF and braced well, 100% sealed. It fits perfectly in the back well area of an f-body. It is carpeted and looks professional, I have pictures if you're interested. The subs can handle between 500 and 1500watts total to all 3. It's 2 weeks old. If anyone in Arizona is interested, email me.. bdietz@email.arizona.edu